"Hubble: A Journey Through Space and Time" By Edward J. Weiler Published April 2010 by Abrams in collaboration with NASA

Twenty years ago this week, on April 24, 1990, the Hubble Space Telescope was placed in orbit, and revolutionized astronomy with its crystal-clear views of the cosmos. For astrophysicist Dr. Edward J. Weiler, who worked on the project for NASA, it also wiped out his college studies.

“The most intriguing impact was how much I learned in graduate school that was overturned by Hubble,” Weiler says. “It convinced me that the universe we observe doesn’t read the same textbooks.”

One basic discovery: The universe began making stars and galaxies much earlier than we thought possible.

Weiler says shortly after the Hubble was repaired following its initial launch, the team focused on just one fraction of the sky, 1/200 millionth of what you see from Earth. It was, he says, “like looking through the eye of a needle held out at the end of your arm.” Just that tiny area, though, contained an amazing 5,000 galaxies.

By studying the speed and distance of specific variable stars in nearby galaxies, the Hubble also provided a more accurate age for the start of the universe — 13.7 billion years ago. That supported the Big Bang, and the expanding universe theory proposed by the telescope’s namesake, astronomer Edwin P. Hubble.

Thanks to a maintenance mission in 2009, Hubble will outlive its 20th birthday, and should function until 2014, perhaps beyond. Then, a successor, the James Webb Space Telescope, will hopefully be launched to continue to deliver images without the filter of Earth’s atmosphere.